This disclosure relates to a sealed, refluxing heat transfer device adapted to replace the secondary or intermediate heat exchanger in a nuclear reactor used for generation of steam for power purposes. The present intermediate heat exchanger provides the required physical isolation between the primary reactor coolant loop and a secondary liquid loop in which steam is generated. It utilizes the available heat transfer rates common to a heat pipe, but requires no wicking materials. It further serves to physically isolate noncondensible gases, which can be readily recovered.
These results are accomplished by use of a sealed vapor chamber where the primary loop and the steam line are in proximity to one another, but not in contact. Heat transfer occurs within the vapor chamber by use of the two phase liquid-vapor-liquid process common to heat pipes.
It is a first object of this invention to provide an efficient intermediate heat exchanger for use in nuclear reactors which will effectively isolate steam generating equipment from possible contamination with radioactive materials. The intermediate heat exchanger also reduces the danger of catastrophy which would accompany any leak between the primary loop and the steam generating piping were they to be directly coupled to one another. This is of special significance in the design of liquid metal cooled reactors.
Another object of this disclosure is to provide an intermediate heat exchanger which eliminates the requirement of utilizing secondary liquid pumps and the problems of maintaining such pumps.
Another object of this invention is to provide an intermediate heat exchanger with no moving mechanical elements, and where all elements of the heat exchanger itself will be encased within a sealed vapor chamber. In many instances, the working pressure within the sealed vapor chamber will be less than atmospheric pressure. Rupture of the chamber will therefore not result in an explosive condition, since the reduced pressure within it will contain its elements and materials within its normal confines.